Waterstop for concrete form separator

ABSTRACT

The device for preventing infiltration of rainwater, etc. at the locations of separators in concrete structure is constituted by a thermal (4) in the form of a resin cylinder (1) which has an internally tube (2) made of metal, etc. inserted into one end and whose other end (12) has a water prevention plug (7) of water-swellable material fixed in it and a water prevention ring (3) of water-swellable material fixed around it. A screw portion (6) at the end of a separator (5) in concrete (A) is screwed into the tube (2) fitted in one end of the cylinder (1). Pref. the other end of the cylinder is flared (9) and has a groove into which the water prevention (3) fits.

BACKGROUND OF THE INVENTION

1. Field of the Invention:

The present invention relates to a device for preventing, in a concretestructure such as a concrete wall, rainwater or like from penetratingthrough a concrete wall surface into the concrete structure around eachseparator which has been left embedded therein.

2. Description of the Prior Art:

In constructing the above-mentioned concrete structure such as theconcrete wall, the separator is usually used to hold each pair of moldsopposed to each other at a predetermined distance and such separator isleft embedded in the concrete structure after completion of thisstructure. More particularly, each separator is provided on its opposedends with separator terminals, respectively, and these separatorterminals are removed when the molds are disassembled upon completion ofthe construction. This results in formation of a recess in the concretewall in a region which has been occupied by each of the separatorterminals. Such recess must be filled up in a suitable manner forwater-sealing effect.

One well-known device for prevention of rainwater or like frompenetrating in the region of each separator into the concrete structurehas already been described in Utility Model Publication No. 43-27286,published in Japan on Nov. 12, 1968.

However, in this device of well known art, plugs are secured withadhesive into the recesses formed in the concrete wall surface after theseparator terminals have been removed from the respective separators.Such feature leads to various problems as follow:

(1) It is difficult for adhesive to spread uniformly between the innersurface of the recess and the associated plug and often a gap is formedtherebetween.

(2) A gap is progressively formed between the inner surface of therecess and adhesive as the years go by, due to factors such ascontraction of concrete and adhesive occurring during hardening thereof.

(3) A gap is formed also between the concrete wall and the separator.

(4) A covering depth between the concrete wall surface and the separatoris relatively poor.

In consequence, said gaps serve as water passages by which rainwater orlike penetrates from the wall surface through the gap between the recessin the concrete wall and the plug into the other gap between theconcrete wall and the separator, causing the separator to be rusted.

These problems result in:

(a) Durability of the structure deteriorates.

(b) Rust containing water exudes over the wall surface and injures thebeauty of the wall surface.

SUMMARY OF THE INVENTION

A principal object of the present invention is, therefore, to provide adevice adapted to effectively prevent rainwater or like from penetratingthrough the wall surface into the concrete wall around each separatorleft therein and thereby to overcome the problems as set forth above.

The present invention provides a device for prevention of rainwater orlike from penetrating into a concrete structure around each separatorleft embedded therein, said device comprising a hollow cylinder ofsynthetic resin, the latter including a female threaded cylinder made ofmetal or other material embedded in the interior at one end thereof andwater-swollen damming-up outer rings fixed on the outer periphery so asto serve together as terminals, a threaded cylindrical portion formed atone end of each of said terminals being engaged with a male threadedportion formed around the corresponding end of the separator, and saidcylinder of synthetic resin further including a plug provided with awater-swollen damming-up inner ring fixed into the interior at the otherend thereof.

When each of the separator terminals is incorporated with the deviceaccording to the present invention, any quantity of water havingpenetrated into the gap defined between the concrete wall A and thecylinder 1 of the terminal 4 is dammed up by the water-swollendamming-up outer ring 3 against further penetration further inwards.

On the other hand, any quantity of water having penetrated into the gapdefined between the cylinder 1 of the terminal 4 and the plug 8 isdammed up by the water-swollen damming-up inner ring 7 againstpenetration further inwards.

BRIEF DESCRIPTION OF THE DRAWINGS:

FIG. 1 is a longitudinal sectional view illustrating an important partof a concrete structure incorporated with a device for prevention ofrainwater or like from penetrating thereinto constructed according to anembodiment of the present invention;

FIG. 2 is a frontal view illustrating one of terminals forming part ofsaid device;

FIG. 3 is a side view of said terminal;

FIG. 4 is a frontal view illustrating a plug provided with awater-swollen damming-up inner ring;

FIG. 5 is a side view of said plug; and

FIG. 6 is a longitudinal sectional view illustrating an important partof a concrete structure constructed with use of said terminals butbefore the plug is secured thereto.

DETAILED DESCRIPTION OF THE INVENTION:

The present invention will be described with respect to an embodiment asillustrated by the accompanying drawings. Referring to the drawings, areference A designates a concrete wall and a reference 4 designates aterminal adapted to be threaded onto a corresponding end of eachseparator 5 which is, in turn, adapted to be embedded in said concretewall A. The terminal 4 comprises a hollow cylinder 1 made of syntheticresin, including a female threaded cylinder 2 received and embedded inthe interior at one end thereof, a flange 9 provided therearound at theother end, an outwardly flared recess 10 formed in the inner wallthereof at said other end and a water-swollen damming-up outer ring 3fixed around the outer periphery thereof adjacent said flange 9. Areference 5 designates a separator provided at opposite ends withrespective male threads 6 having their base ends in the form of stoppers11. A reference 8 designates a plug made of synthetic resin having atapered head 12 at its base end, circumferential grooves 13, 14 formedtherearound at its base end and front end, respectively, so that thecircumferential groove 13 receives a water-swollen damming up inner ring7 slightly projecting from the outer periphery of said plug 8 and thecircumferential groove 14 is coated with suitable water-swollen sealingagent, if necessary. A reference 15 designates a water-swollendamming-up outer ring fixed around the separator 5 at its middleposition.

Examples of the water-swelling waterstop material to be used for thewater-swelling rings 3, 7 and 15 include acryl, vinyl and inorganicwater-swelling resins. It is particularly preferable to use a flexiblematerial containing water-swelling polyurethane which comprises amixture of a water-swelling polyurethane resin, and for example,natural, synthetic or reclaimed rubber, therefor.

Such a flexible material as described above may be obtained by kneadingone or more polyether polyols of the following general formula:

    R[(OR).sub.n ].sub.p

wherein R represents a polyhydric alcohol residue; (OR) represents apolyoxyalkylene chain comprising oxyalkylene groups each having anoxyethylene group and an alkylene group carrying three or four carbonatoms, provided that the content of the oxyethylene groups amounts to 20to 100% of the total molecular weight;

n is a number corresponding to the degree of polymerization of theoxyalkylene groups and giving a hydroxyl group equivalent of 200 to2500; and

p is a number of 2 to 8, preferably 2 to 4; together with urethanepolymer(s) having polyisocyanate groups, a crosslinking agent and therubber as defined above followed by curing.

Examples of said polyhydric alcohol include dihydric alcohols such asethylene glycol and propylene glycol; trihydric alcohols such asglycerol and trimethylolpropane; tetrahydric alcohols such as erythritoland pentaerythritol; pentahydric alcohols such as arabitol and xylitol;and hexahydric alcohols such as sorbitol and mannitol.

Said polyether polyols may be obtained by adding alkylene oxide(s) tothese polyhydric alcohols in such a manner as to give the desiredmolecular weight. Either random or block addition may be employedtherefor. When the content of the oxyethylene groups is less than 20%,the resulting material is unsatisfactory as a waterstop material. Anypolyisocyanates may be employed. The content of the terminal isocyanategroups may be 1 to 12%, preferably 2 to 7%.

Example of said crosslinking agent include polyols and polyamines eachcarrying two to six active hydrogen atoms per molecule and has anaverage molecular weight per active hydrogen atom of 30 to 15000, forexample, low-molecular weight polyols, addition polymers oflow-molecular weight polyols and alkylene oxides and addition polymersof low-molecular weight polyamines and alkylene oxides, as well asmixtures thereof.

It is preferable that the flexible material as described above contains20 to 800 parts of water-swelling polyurethane resin per 100 parts ofthe rubber.

Other examples of preferable flexible materials are those obtained byfurther adding hydraulic material(s) to a composition comprising saidwater-swelling polyurethane resin and rubber. Examples of availablehydraulic materials include Portland cement, blast furnace cement,colloidal cement and gypsum. It is preferable to employ a curingaccelerator for cement comprising calcium aluminate simultaneouslytherewith. A flexible material comprising such a hydraulic material hasan advantage that it shows little shrinkage when dried. It is preferablethat the hydraulic material is blended in an amount of 20 to 30 partsper 100 parts of the mixture of the water-swelling polyurethane andrubber.

The above flexible material may further contain appropriatewater-absorbing material(s). Examples of the water-absorbing materialsinclude those mainly comprising an α,β-unsaturated compound, whichcarries one or more carboxyl groups or those capable of being derivedthereto such as carboxyl, carboxylate, carboxylic imide, carboxylicamide or carboxylic anhydride groups per molecule, and optionallypolymerized with other α,β-unsaturated compound(s) and/or modified withisocyanate(s).

Examples of such a water-absorbing resin include conventionalwater-absorbing polymers such as starch-acrylic acid graft copolymer, asalt of styrene/maleic anhydride copolymer, crosslinked poly(sodiumacrylate), vinyl ester/ethylenically unsaturated carboxylic acids, andsaponified products or derivatives thereof.

The flexible material may be further vulcanized with the use of acrosslinking agent such as sulfur.

It is preferable that the composition of the flexible material may becontrolled in such a manner as to give a water-swelling ratio of theresulting molded article of 10 to 350%, still preferably 40 to 250%.

FIG. 5 is a side view of said plug and FIG. 6 is a longitudinalsectional view illustrating an important part of a concrete structureconstructed with use of said terminals but before the plug is securedthereto. Referring to FIG. 6, a reference B designates a concrete moldhaving a through-hole 16 at an appropriate location. A reference 17designates a connecting bolt having male threads 18, 19 on oppositeends, respectively. A reference 20 designates a mold clamping leverhaving a threaded hole 21 formed in a base end thereof.

Now it will be considered how to construct a concrete wall using thedevice for prevention of rainwater or like from penetrating thereintoaccording to the present invention. As shown in FIG. 6, one end of thefemale threaded cylinder 2 of the terminal 4 carrying the water-swollendamming-up outer ring 3 fixed around the cylinder 1 is advanced inengagement with the male thread 6 of the separator 5 to the stopper 11of said male thread 6 and the male thread 18 of the connecting bolt 17is threaded into the other end of said female threaded cylinder 2.

Then, the connecting bolt 17 is inserted into the through-hole 16 of themold B and the threaded hole 21 of the mold clamping lever 20 isthreaded on the male thread 19 of said connecting bolt 17 so that themold B is held between the terminal 4 and the mold clamping lever 20.Although FIG. 6 illustrates only the mold at one side, the arrangementis same at the opposite side and a pair of molds are held at apredetermined distance from each other. Thereafter, vertical andhorizontal batters are combined on the outside of the mold B in theconventional manner, although not shown, these batters are clampedtogether by suitable means through the mold clamping levers 20 so as tofix the mold. Then, concrete may be placed into an internal spacedefined between the pair of the molds to construct the concrete wall A.

Upon hardening of concrete which forms the concrete wall A, the moldsare disassembled and then the connecting bolts 17 are threaded out.

Then, as seen in FIG. 1, the plug 8 carrying the water-swollendamming-up inner ring 7 is forced into the hollow interior of thesynthetic resin cylinder 1 from the other end and the head 12 of saidplug 8 is engaged in the recess 10 of the cylinder 1 so as to fill saidrecess 10 with said head 12.

Said water-swollen damming-up outer ring 3 performs the similar functioneven when said outer ring 3 is fixed around the cylinder 1 at any otherposition. Additionally, as illustrated in FIG. 6, the water-swollendamming-up ring 15 may be fixed around the separator 5 at any positionto further improve water-sealing effect.

The device for prevention of rainwater or like from penetrating into theconcrete structure around each of the separators constructed inaccordance with the present invention provides significant effects asfollow:

(1) The separator terminals are of the embedded type, therefore,

(a) Neither application of separating material nor operation of theterminal removal is required so that the operation efficiency isdrastically improved and the work cost can be reduced.

(b) Concrete crack possibly associated with removal of the terminals canbe avoided.

(c) Finish of the terminals is accomplished simply by mounting theplugs, enabling the finished appearance to be aesthetically improved.

(2) The female threaded cylinder made of metal or other material isembedded into the synthetic resin cylinder of the terminal at one endthereof and one end of said female threaded cylinder is engaged with themale thread on the separator. Accordingly, it is possible to obtain arelatively large covering depth from the wall surface to the componentssuch as the separator and the metallic female threaded cylinder. Thismeans that the metallic components such as the separator and the femalethreaded cylinder are prevented from being rusted due to rainwater orlike would otherwise penetrate through the wall surface into thestructure and thereby deterioration of the concrete structure isavoided. This is effective particularly for the structure at the seasideexposed to injury from salt.

(3) Rainwater or like penetrating through the wall surface into the gapdefined between the concrete wall and the terminal is dammed up by thewater-swollen damming-up outer ring fixed around the terminal againstfurther penetration inwards and rainwater or like penetrating into thegap defined between said terminal and the plug thereof is dammed up bythe water-swollen damming-up inner ring disposed therebetween againstfurther penetration inwards.

With a consequence, it is effectively avoided that rainwater or likemight penetrate through the wall surface, through the gap definedbetween the concrete wall and the terminal and through the gap definedbetween the terminal and the plug into the concrete wall around theseparator. Therefore:

(a) The separator is prevented from being rusted, improving thedurability of the concrete structure.

(b) There is no possibility that rust containing water exudes over thewall surface, injuring the aesthetic appearance of the wall surface.

(4) Rainwater or like penetrating into the gap defined between theconcrete wall and the terminal and/or the gap defined between theterminal and the plug swells the water-swollen damming-up rings disposedwithin these gaps so that the damming-up rings thus swollen are nopressed against the concrete wall and the terminal and/or the terminaland the plug, respectively, perfectly filling up these gaps and therebyfurther reliably preventing rainwater or like from penetrating into theconcrete wall around the separator terminal.

(5) Arrangement is simple, enabling it to be easily manufactured as alow cost and providing a stable fixation.

What is claimed is:
 1. A waterstop for a concrete form separator, comprising:(A) a terminal member including:(1) a hollow cylinder of synthetic resin, having opposite ends, an interior, and an outer peripheral surface; (2) a female threaded cylinder made of metal mounted in the interior at one end of said synthetic resin hollow cylinder; and (3) a water-swollen damming-up outer ring mounted at the other end of said synthetic resin hollow cylinder and around the outer peripheral surface of said synthetic resin hollow cylinder and having sufficient thickness for preventing rainwater from penetrating into a gap defined between said synthetic resin hollow cylinder and a concrete structure; (B) a separator member having a male threaded portion engaging with said female threaded cylinder of said terminal; and (C) a plug mounted within the interior of said other end of said synthetic resin hollow cylinder, said plug having a water-swollen damming-up inner ring mounted therearound and having a sufficient thickness for preventing rainwater from penetrating through a gap defined between said synthetic resin hollow cylinder and said plug.
 2. A waterstop for a concrete form separator according to claim 1, wherein said plug comprises:a tapered head at a base end thereof, said tapered head comprising a tapered outer peripheral surface portion of said plug; and a circumferential groove in said plug adjacent said tapered head to receive said water-swollen damming-up inner ring therein.
 3. A waterstop for a concrete form separator according to claim 2, wherein said inner ring comprises flexible material.
 4. A waterstop for a concrete form separator according to claim 2, wherein said inner ring is fixed to said plug.
 5. A waterstop for a concrete form separator according to claim 1, wherein said outer ring comprises flexible material.
 6. A waterstop for a concrete form separator according to claim 1, wherein said outer ring is fixed to the outer peripheral surface of said synthetic resin hollow cylinder. 